WO2019211405A1

WO2019211405A1 - Receiving unit and power transmission system for wireless power transmission

Info

Publication number: WO2019211405A1
Application number: PCT/EP2019/061304
Authority: WO
Inventors: Samuel Vasconcelos Araujo; Michael JIPTNER
Original assignee: Kardion Gmbh
Priority date: 2018-05-02
Filing date: 2019-05-02
Publication date: 2019-11-07
Also published as: US20210336484A1; DE102018206714A1; DE112019002243A5

Abstract

The invention relates to a receiving unit (200) configured to interact with a transmission unit (100), separate from the receiving unit, for the purpose of wireless power transmission, which transmission unit (100) has a primary coil (L₁) suppliable with a supply voltage (UV), wherein the receiving unit (200) has a secondary coil (L₂), to which a first DC link capacitor (C_Z,1) is connected via a rectifier (210), and a power unit (240), to which a load (225) and/or an energy store (220) are connected, wherein the receiving unit (200) has a second DC link capacitor (C_Z,2), to which the power unit (240) is connected, wherein the first DC link capacitor (C_Z,1) and the second DC link capacitor (C_Z,2) are connected to one another such that they are disconnectable by means of a switch (S₇), and wherein the receiving unit (200) has an auxiliary supply unit (250) that is connected to the rectifier (210) for the purpose of supplying voltage and that is configured to close the switch(S) in order to connect the first DC link capacitor (C_Z,1) to the second DC link capacitor (C_Z,2) when an output voltage (U_out,H) of the auxiliary supply unit (250) exceeds a prescribed threshold value.

Description

Receiving unit and energy transmission system for wireless energy transmission

description

The present invention relates to a receiving unit, which is set up to cooperate for wireless energy transmission with a transmitting unit separated from the receiving unit, and to a power transmission system having such a receiving unit and a transmitting unit for wireless energy transmission.

To supply energy to consumers and in particular to charge energy storage devices, a wireless, in particular inductive, energy transfer can be used. With this ad of the energy transmission, a magnetic field can be generated in a transmitting unit with a primary coil, which induces a voltage and thus a current flow in a receiving unit with a secondary coil.

This type of energy transfer can be used in particular in the so-called transcutaneous energy transfer, in which the receiving unit is arranged or implanted under the skin in a human body. Such a transcutaneous energy transmission is advantageous, for example, in circulatory or cardiac assist systems (so-called VAD systems, or "Ventricular Assist Device"), because then there is no permanent wound in the skin through which a cable is guided.

In such a power transmission system can then be provided in the body to be arranged in the receiving unit, a power unit for supplying a load or for charging an energy storage unit, which is powered by the voltage induced in the secondary coil. However, it can be problematic in this case that, at the beginning of the energy transmission, the power unit or other parts are disturbed, in particular if For example, no power supply unit is present or this is just separated.

Proceeding from this, the object of the invention is to further improve the systems known in the prior art for wireless energy transmission and to avoid unstable operating states, in particular during the starting process or start-up.

According to the invention, a receiving unit and an energy transmission system with the features of the independent patent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

The invention is based on a receiving unit which is set up to cooperate for wireless energy transmission with a transmitting unit separate from the receiving unit, or of an energy transmission system for wireless energy transmission with a transmitting unit and such a receiving unit separate from the transmitting unit. The transmitting unit has a primary coil, which can be supplied with a supply voltage. For this purpose, as a rule, an inverter, for example with suitable semiconductor switches, is provided in order to generate an oscillation of the voltage in the primary coil with a supply voltage present as a direct voltage. This can be generated by means of the transmitting unit, a magnetic alternating field.

The receiving unit accordingly has a secondary coil to which a first intermediate circuit capacitor or generally a DC link capacitor is connected via a rectifier. The rectifier may in particular be a passive rectifier with suitable diodes. However, an active rectifier with, for example, suitable semiconductor switches is also advantageous. The first DC link capacitor, which is charged in the case of energy transfer, is used in particular for smoothing the alternating voltage induced in the secondary coil and then rectified. As already mentioned, this type of wireless energy transmission involves an inductive energy transmission.

In addition, a power unit (or a power stage) is provided in the receiving unit, to which a consumer and / or an energy store are connected. While the power unit may in particular be a step-down converter with, for example, suitable semiconductor switches, an accumulator or a rechargeable battery may be considered as the energy store.

In a conventional receiving unit, the power stage is usually connected directly to the (single) DC link capacitor and above to the rectifier, so that the power unit with active transmitting unit - by means of wireless or inductive energy transmission - supplied with voltage or energy becomes.

However, if the receiving unit has no energy store or if it has to be disconnected due to an error, for example, the receiving unit (in particular with integrated electronics) must start up automatically as soon as the transmitting unit begins to transmit energy. This means that a start-up or start-up of an auxiliary supply with, for example, signal electronics, control electronics and the like must take place, which is supplied directly from the DC link of the resonant converter or via the DC link capacitor. During this transient startup operation, an unstable operating condition may occur which may destroy the system, i. the receiving unit, can lead.

According to the invention, it is now provided that the receiving unit has a second intermediate capacitor, to which the power unit is connected, wherein the first intermediate circuit capacitor and the second intermediate circuit capacitor are separably connected to one another via a switch. The DC link capacitance is therefore divided into two parts, so to speak, which can be connected and disconnected by the switch. In particular, the first and second DC link capacitance are connected in parallel when the switch is closed. As a switch here is a semiconductor switch, in particular a MOSFET or IGBT, into consideration. Conceivable, however, are also other circuit breakers.

Furthermore, it is provided that the receiving unit has an auxiliary supply unit, which is connected to the rectifier for supplying voltage, and which is set up to close the switch for connecting the first intermediate circuit capacitor to the second intermediate circuit capacitor, that is to turn the switch on when an output voltage of the auxiliary power supply unit exceeds a predetermined threshold value. This threshold value is preferably 15 V, since then all the components of the auxiliary supply unit operate in their rated voltage range and a stable operating point for starting up is ensured. In this way, it is thus achieved that the second intermediate circuit capacitor - and therefore the power unit - are initially not connected to the secondary coil and the rectifier, but that at the beginning of the energy transmission from the transmitting unit to the receiving unit, initially only the first intermediate circuit capacitor is charged and the auxiliary supply unit are supplied with voltage. Only when the output voltage provided by the auxiliary supply unit exceeds the threshold value, that is, the second intermediate circuit capacitor and thus the power unit are connected or connected.

In this way, it is thus possible to ensure that no unstable state occurs during startup, which is usually caused by uncontrolled pulsing of circuit breakers in the power unit because a relatively high voltage (usually more than 10 V) is already present at the circuit breaker. rend the other components such as microcontroller and driver units have not yet started properly. With the proposed receiving unit however, components such as microcontroller and driver circuitry may have been fully powered up next. This prevents the unstable state.

Preferably, the auxiliary supply unit has an optical coupler, via which the switch can be controlled. In addition, a voltage comparator can then be provided which is set up to control the optical coupler for closing the switch if the output voltage of the auxiliary supply unit exceeds the predetermined threshold value. In this case, the switch is designed in particular as an N-MOSFET. The optical coupler can have a photodiode and an integrated driver.

Alternatively, it is also preferred if the auxiliary supply unit has a voltage divider for generating the output voltage, which is connected with its voltage divider output to a switching terminal of the switch. The output voltage results in particular by dividing the voltage at the first DC link capacitor. The voltage divider is then in particular connected so that the switch is closed when the output voltage exceeds the predetermined threshold. In this case, the switch is designed in particular as P-MOSFET, at its gate terminal, i. at its switching connection, the voltage divider output is connected.

Both versions allow a particularly safe and fast start-up of the receiving unit and can be used as required. The semiconductor switches used may in both cases in particular have a voltage class of 20 V. In particular, values of, for example, 1 μW are considered as a resistance for drain-source in order to reduce losses. Likewise, in both cases, charging the first intermediate circuit capacitor when the energy storage unit is connected by the intrinsic diode of the MOSFETs can be achieved, which may be necessary, for example, in the regular operation of the receiving unit.

The invention further provides an energy transmission system for wireless energy transmission with a receiving unit according to the invention and a separate transmitting unit which has a primary coil which can be supplied with a predetermined supply voltage.

Although the presented receiving unit and the presented energy transmission system for any type of wireless or inductive energy transmission are advantageous, it is particularly useful if the receiving unit is designed to below a skin in a human or animal body arranged, in particular implanted to become, and / or when the transmitting unit is adapted to be placed on a skin outside of a human or animal body. Thus, the energy transmission system (or the receiving unit as part of it) serves the transcutaneous energy transmission mentioned above.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

The invention is illustrated diagrammatically by means of an exemplary embodiment in the drawing and will be described below with reference to the drawing.

Fig. 1 shows schematically an inventive energy transfer system in a preferred embodiment.

FIG. 1 schematically shows an inventive energy transmission system 300 for wireless energy transmission in a preferred embodiment. The energy transmission system in this case has a transmitting unit 100 and a separate receiving unit 200, wherein the receiving unit 200 is designed as a receiving unit according to the invention in a preferred embodiment.

The transmitting unit 100 has a primary coil Li, to which an inverter 110, which has four semiconductor switches designated by Si to S ₄ , for example MOSFETs or bipolar transistors, can be connected to a supply voltage Uv or with this supply voltage is available. In addition, a pre-filter 120 with unspecified components and a compensation capacitance between the inverter 1 10 and the primary coil Li are connected. The compensation capacitance serves as a reactive power compensation for resonant control (control with the design frequency).

When applied supply voltage Uv and suitable control of the inverter so a magnetic alternating field can be generated by means of the coil Li.

The receiving unit 200 has a secondary coil l_2, to which a first intermediate-circuit capacitor Cz _{, i is} connected via a compensation capacitor and a rectifier 210. A second intermediate circuit capacitor Cz _{, 2 is} connected to the first intermediate circuit capacitor Cz _, _i via a switch S7. By means of the switch S7, the two DC link capacitors can thus be connected in parallel or separated from one another. In the present example, the switch S7 is designed as an N-MOSFET, with drain terminal D, source terminal S, and gate terminal G.

Connected to the second DC link capacitor Cz _{, 2} is a power unit or power stage 240, which in this case may be two semiconductor switches S5 and S6, which may be formed, for example, as MOSFETs, IGBTs or bipolar transistors, and together with an inductance and a capacitor serve as a buck converter has. An energy storage unit 220 and a consumer 225 are then connected by way of example to the power unit 240. By way of example, the energy storage unit can be separated from the power unit 240 by means of an unspecified switch 221, for example in the case of a fault. The energy storage unit 220 may in particular be an accumulator or a rechargeable battery. At the energy storage unit, for example, a voltage L t with a current t can be set using the mentioned buck converter.

The rectifier 210 is designed as a passive rectifier with four unspecified diodes. It is also conceivable, however, the use of an acti rect rectifier with, for example, Flalbleiterschaltern.

Furthermore, the receiving unit 200 has a fly-power supply unit 250, which is connected to the rectifier 210, for example, by means of a switch, a diode, and a capacitor, which is not shown, and functions similarly as the power unit 240 as a step-down converter. In this way, the auxiliary supply unit 250 itself can be directly supplied with the voltage induced in the secondary coil L2 and produce a _{predetermined} regulated output voltage U _0U t, H. The regulation of the output voltage U _0U t, H takes place by means of the so-called pulse width modulation, ie via the switch-on time of the active switch of the auxiliary supply unit 250 in relation to the switching period.

Furthermore, a (conventional) voltage _comparator 252 is provided, to which the output voltage U _0U t, H of the auxiliary _{supply unit} 250 is applied, and which is connected to an optical coupler 251. The optical coupler 251 in turn is connected, inter alia, to the gate terminal G of the switch or N-MOSFET S7.

In this case, the voltage comparator 252 and the optical coupler 251 are adapted to turn on or off the switch S7, and so on second DC link capacitor Cz _{, 2} together with the power unit 240 to the first DC link capacitor Cz _{, i} connect when the output voltage U _0U t, H _exceeds a threshold that can be suitably specified or set. The voltage comparator 252 acts non-inverting and switches its output voltage on reaching a positive threshold (preferably about 15 V) at the input.

The receiving unit 200 can now be configured in particular to be arranged or implanted under a skin, which is indicated here by 310, and used, for example, for a circulation or cardiac support system. In particular, the energy storage unit 220 can be used for the energy supply of such a circulatory or cardiac assistance system.

When correspondingly positioned outside or on the skin 310 transmitting unit 100 - with a corresponding positioning - a coupling between the primary coil Li of the transmitting unit 100 and the secondary coil L2 of the receiving unit 200 is achieved.

If now the transmitting unit is controlled or operated such that an alternating magnetic field is generated by means of the primary coil Li, a voltage or a current flow in the secondary coil L2 is induced by the coupling. This in turn causes the first intermediate circuit capacitor Cz _{, i to be} charged and the auxiliary supply unit 250 to be supplied with voltage.

As soon as the output voltage U _0U t, H of the auxiliary _{supply unit} exceeds the threshold value, as mentioned, the power unit 240 is connected to the following components and also supplied with voltage. In this way, a safe startup of the receiving unit 200 can be achieved.

Claims

claims

1. receiving unit (200) which is set up to cooperate for wireless energy transmission with a transmitting unit (100) separate from the receiving unit, which transmitting unit (100) has a primary coil (Li) which is connected to a supply voltage (200). Uv) can be supplied,

wherein the receiving unit (200) has a secondary coil (L2) to which a first intermediate circuit capacitor (Cz _{, i} ) is connected via a rectifier (210), and a power unit (240) to which a consumer (225) and / or or an energy store (220) are connected,

characterized in that the receiving unit (200) has a second intermediate circuit capacitor (Cz _, 2) to which the power unit (240) is connected, the first intermediate circuit capacitor (Cz _{, i} ) and the second intermediate circuit capacitor (Cz _, 2 ) are separably connected to one another via a switch (S7), and in that the receiving unit (200) has an auxiliary supply unit (250) which is connected to the rectifier (210) for voltage supply and which is set up to operate the switch (S7 ) for connecting the first DC link capacitor (Cz _{, i} ) to the second DC link capacitor (Cz _, 2) when an output voltage (U _{0Ut, H} ) of the auxiliary _{supply unit} (250) exceeds a predetermined threshold value.

Second receiving unit (200) according to claim 1, wherein the switch (S7) as a semiconductor switch, in particular as a MOSFET is formed.

3. receiving unit (200) according to claim 1 or 2, wherein the Hilfsversor- supply unit (250) comprises an optical coupler (251), via which the switch (S7) is controllable. The receiving unit (200) of claim 3, wherein the auxiliary supply unit (250) further _{comprises a voltage comparator} (252) _{adapted to drive} the optical coupler (251) to close the switch (S7) when the output voltage (U _0U t, H) of the auxiliary supply unit (250) exceeds the predetermined threshold value.

Receiving unit according to claim 1 or 2, wherein the auxiliary supply unit comprises a voltage divider for generating the output voltage (Uout.H).

Receiving unit according to claim 5, which is designed such that the switch is closed when the output voltage exceeds the predetermined threshold.

Receiving unit (200) according to one of the preceding claims, wherein the power unit (240) has a step-down converter.

8. receiving unit (200) according to any one of the preceding claims, which is adapted to be arranged below a skin (310) in a human or animal body.

9. Energy transmission system (300) for wireless energy transmission with a transmitting unit (100) and a separate receiving unit (200) according to any one of the preceding claims, wherein the transmitting unit (100) has a primary coil (Li), which with a preg - Benen supply voltage (Uv) can be supplied.

10. The energy transfer system of claim 9, wherein the transmitter unit is configured to be disposed on a skin outside of a human or animal body.